The present invention relates to an electronic timepiece with indicator hands integrally formed with figures or the like.
Conventionally, electronic timepieces with indicator hands integrally formed with figures, such as characters, have been utilized.
In the conventional electronic timepiece with indicator hands, the hand functioning as an indicator hand is structured by a needle-shaped second hand or disk-formed second hand wherein the second hand serves also as the indicator hand. Meanwhile, also in the conventional timepiece having an indicator hand moved only by user""s operation, the indicator hand has been used also as a time hand to show time. Alternatively, the indicator hand has been moved by interlocking with the time hand.
Consequently, in any of the electronic timepieces, there is nothing more than having one indicator hand serving also to show a time. With one indicator hand only, it is impossible to provide a variety of motions to the figure, such as a character, and thus it has been impossible to give a variety of indications.
Meanwhile, although there have existed the timepieces having indicator hands moving at all times, these are nothing more than merely having a figure or the like on a disk-formed second hand or needle-like second hand. Thus, a variety of indications, e.g. providing a variety of motions, have been impossible to perform.
Also, where the indicator hand serves also as a time hand or is moved by interlocking with the time hand, the figure or the like integrally formable on the indicator hand is restricted in size by the restriction due to moment of the hand. Thus, it has been impossible to use an indicator hand capable of providing a variety of indications.
It can be considered as a method of solving this problem and realizing a variety of indications by the indicator hand to provide a plurality of indicator hands separately from the time hands and providing a motor to rotatively drive the indicator hands so that the indicator hands are structured to reciprocally move by and rotating the motor forward and reverse by a constant amount. However, if the indicator hands is merely reciprocally moved, there is a fear that the indicator hand jumps due to impact or the like resulting in instability of indicative motion.
As a method for solving this problem, it is an effective method to provide such a mechanism as restricting the rotation range of the indicator hands within a predetermined range.
In this case, the restriction range is preferably given variable in respect of providing more various indications.
Also, in the case of providing a mechanism for merely restricting the indicator-hand rotation range to a predetermined range, where the motor uses a stepping motor for timepieces as generally used in the timepieces, there is a problem that the stepping motor, when stopped in a particular region, becomes inoperative of subsequent rotational movement.
That is, the stepping motor for timepieces is rotated forward by supplying a forward driving pulse alternately to a pair of terminals on the motor coil, as described in Japanese Patent Laid-open No. 127365/1979. In reverse rotation, a forward driving pulse is first supplied to once cause slight rotation and then a reverse driving pulse is supplied to cause reverse rotation. In this manner, because there exists a region where rotation is impossible to occur without giving impetus for reverse rotation, forward rotation is first made to provide impetus and then causing reverse rotation. However, as shown of a typical view of the stepping motor in FIG. 11, if the rotor magnet is stopped at a particular region, impetus cannot be given to the rotor magnet 1101, thus possibly resulting in a case of impossibility of subsequent rotation. Hereunder, described in detail is the operation where the rotor magnet 1101 is brought into inoperative.
In FIG. 11, 1101 is a rotor magnet having N and S poles, 1102 is a stator, 1103 is a convex part attached on the rotor magnet 1101, and 1104 is a convex part attached on a fixing part. A forward driving pulse and a reverse driving pulse are supplied to a coil (not shown) to thereby applying a magnetic field for rotating the rotor magnet 1101 forward and reverse.
In the meanwhile, it is assumed that a magnetic field is being applied in an X-axis direction in FIG. 11(a). If forward rotation is given in a direction of the arrow and the convex part 1103 and the convex part 1104 become engagement to stop the rotor magnet 1101 in an illustrated position, it is impossible to give impetus for reverse rotation. Thus, reverse rotation is impossible to cause. Meanwhile, also in FIG. 11(b), reverse rotation is similarly impossible to cause. That is, although when the motor stops in the second quadrant and fourth quadrant reverse rotation can be made, in the first quadrant and third quadrant there is a non-rotation region where the motor cannot be rotated reverse.
Consequently, by merely providing such a mechanism as restricting the indicator-hand rotation range to a predetermined range, the motor will stop in the non-rotatable region. This results in a fear that the indicator hands cannot be rotatively driven and the operation of the indicator hands becomes unstable.
It is an object of the present invention to provide an electronic timepiece with indicator hands which is capable of offering a variety of indications and preventing the indicator hands from moving unstably.
The present invention utilizes the technological structure as described below in order to achieve the above object.
That is, an electronic timepiece with indicator hands, according to the present invention is characterized by comprising: time hands for showing a time; a first and second indicator hands provided separately from the time hands; rotating means for reciprocally rotating the first and second indicator hands in directions opposite to each other within a predetermined range; and restricting means for restricting a movable range and capable of adjusting a restricting position of the first and second indicator hands.
The rotating means reciprocally rotates the first and second indicator hands in directions opposite to each other. Where the first and second hands are rotating toward the outside of a range restricted by the restricting means due to impact or the like, the restricting means restricts rotation of the first and second indicator hands. Also, where a variety of indications are desired by changing the restriction range of the first and second indicator hands or there is a fear that the first and second indicator hands stop in a non-rotatable region, the restricting means is adjusted to change the movable range of the first and second indicator hands. This makes it possible to provide indicator hands for a variety of indications and an electronic timepiece with indicator hands capable of preventing unstable operation of the indicator hands.
Here, the rotating means may be structured to rotate the first and second indicator hands at the same speed.
Also, the rotating means may be structured to have a stepping motor for timepieces to alternately cause forward rotation and reverse rotation by a predetermined amount, a train wheel for delivering rotation of the stepping motor to the first and second indicator hands.
Furthermore, the restricting means may comprise a first engaging means having a convex part rotatably attached with eccentricity and a second engaging part provided on a wheel included in the train wheel, so that, when the indicator hands are rotating toward the outside of a restricted movable range, the first engaging part and the second engaging part engage to thereby restrict rotation of the first and second indicator hands.
Incidentally, the electronic timepiece may be an electronic wristwatch.